A silencer is discussed in German Patent Document DE 197 01 361 C1.
For diverting compressed air and expanding this, silencers or noise dampers are provided which are suitable for compressed air systems, in particular of vehicles. They generally consist of a pot-like housing which is filled with sound-absorbing material. The housing has an inlet port and an outlet port, the outlet port in many instances being arranged on the pot bottom. In DE 197 01 361 C1, secondary airways are also additionally provided, which take effect when the sound-absorbing material becomes clogged, whether by impurities and/or wetness which freezes. The sound-absorbing material is a filter knit completely filling the pot-like housing. It is customary to wind such a knitted, mostly tubular material cylindrically in one or two plies and to insert a filter cartridge winded this way into the inner volume of the pot-like housing. In free-field vehicle noise measurement according to Directive 70/157 EWG, a sound pressure level of 72 dB(A) is achieved by such a silencer.